Active magnetic position sensor

ABSTRACT

An medical device, comprising an elongate shaft extending along a shaft longitudinal axis and comprising a shaft proximal portion and a shaft distal portion that is sized and configured for insertion into a body. An active magnetic position sensor can be disposed within the shaft distal portion.

PRIORITY CLAIM

This application claims priority to U.S. provisional patent application No. 62/170,466, filed 3 Jun. 2015, which is hereby incorporated by reference as though fully set forth herein.

BACKGROUND a. Field

The instant disclosure relates to a medical device including a position sensor.

b. Background Art

Medical devices such as guidewires, catheters, introducers and the like that include electromagnetic coil position sensors or electrodes for device navigation are used in various medical procedures in the body. For example, it is known to equip a catheter with multiple coils sufficient to allow a position sensing system to detect six (6) degrees-of-freedom (DOF), namely, a three-dimensional (3D) position (X, Y, Z) and a 3D orientation (e.g., roll, pitch, yaw) thereof. However, the design of a coil assembly that can provide such functionality provides challenges, particularly with respect to space constraints.

One known electromagnetic position sensor includes a coil wound symmetrically on a tubular core. Such a sensor may be seen by reference to U.S. Pat. No. 7,197,354, entitled “System for Determining the Position and Orientation of a Catheter” issued to Sobe, hereby incorporated by reference in its entirety as though fully set forth herein. Sobe discloses a core that is hollow, is symmetric about a central axis, and can be scaled in length, inner diameter, and outer diameter for a particular application. A coil is wound on the core in a desired winding pattern. The coil, like the core, is symmetric about the central axis. The sensor can be used in a system to detect position in 3D space defined by three perpendicular axes (X, Y, and Z), as well as rotation about two of the three axes (e.g., pitch and yaw), but the coil cannot detect rotation about the central axis of the core (e.g., roll). Accordingly, a medical device that incorporates a single sensor coil mounted symmetric about the central axis of the medical device only senses five (5) DOF, that is, two orientation parameters, in addition to three position parameters. Despite the DOF limitation, there are nonetheless desirable aspects of the above configuration. For example, the configuration uses minimal space and accommodates an open central lumen.

Electrode mapping systems, particularly the EnSite™ Velocity™ cardiac mapping system available from St. Jude Medical, utilize an electrical field to localize a medical device within a patient's body. As is known, electrodes can be disposed in a spaced apart relationship along an axis of a catheter shaft. The electrodes can detect the electrical field generated by such a system and thereby detect position in 3D space defined by three perpendicular axes (X, Y, and Z), as well as rotation about two of the three axes (e.g., pitch and yaw), but the electrodes cannot detect rotation about the central axis of the catheter shaft (e.g., roll).

SUMMARY

Embodiments of the present disclosure can include a medical device. The medical device can include an elongate shaft extending along a shaft longitudinal axis and comprising a shaft proximal portion and a shaft distal portion that is sized and configured for insertion into a body. An active magnetic position sensor can be disposed within the shaft distal portion.

Embodiments of the present disclosure can include a medical device. The medical device can include an elongate shaft extending along a shaft longitudinal axis and comprising a shaft proximal portion and a shaft distal portion that is sized and configured for insertion into a body. An active magnetic position sensor can be disposed within the distal portion of the elongate shaft. A power source can be electrically coupled with the active magnetic position sensor.

Embodiments of the present disclosure can include a method for determining a position and orientation of a medical device. The method can include generating a signal with an active magnetic position sensor disposed within an elongate shaft of the medical device. The method can include receiving, with a computer, the generated signal from the active magnetic position sensor, wherein the received signal includes information indicative of a position and orientation of the active magnetic position sensor. The method can include determining, with the computer, the position and orientation of the medical device based on the generated signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a diagrammatic view of an exemplary system for performing one or more diagnostic or therapeutic procedures, wherein the system comprises a magnetic field-based medical positioning system, in accordance with embodiments of the present disclosure.

FIG. 2A depicts a cross-sectional side view of a distal portion of a catheter with an active magnetic position sensor, in accordance with embodiments of the present disclosure.

FIG. 2B depicts a side view of an active magnetic position sensor, in accordance with embodiments of the present disclosure.

FIG. 3A depicts a cross-sectional side view of a distal portion of a guidewire with an active magnetic position sensor, in accordance with embodiments of the present disclosure.

FIG. 3B depicts a diagrammatic side view an active magnetic position sensor for use with a guidewire, in accordance with embodiments of the present disclosure.

FIG. 3C depicts a proximal end view of a sensor mounting plug, in accordance with embodiments of the present disclosure.

FIG. 3D depicts an isometric side and proximal end view of the sensor mounting plug, in accordance with embodiments of the present disclosure.

FIG. 3E depicts a cross-sectional side view of a guidewire with an active magnetic position sensor and a sensor mounting plug, in accordance with embodiments of the present disclosure.

FIG. 4 depicts a method flow diagram for determining a position and orientation of a medical device, in accordance with embodiments of the present disclosure.

FIG. 5 illustrates a block diagram of an example of a computer-readable medium in communication with processing resources of a computing device, in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

In some embodiments, and with reference to FIG. 1, the system 10 can include a medical device 12 and a medical positioning system 14. The medical device 12 can include an elongate medical device such as, for example, a catheter, sheath, or a guidewire. For purposes of illustration and clarity, the description below will be limited to an embodiment wherein the medical device 12 comprises a catheter or guidewire (e.g., catheter 12′, guidewire 12″, 12′″). It will be appreciated, however, that the present disclosure is not meant to be limited to such an embodiment, but rather in other exemplary embodiments, the medical device may comprise other elongate medical devices, such as, for example and without limitation, sheaths, introducers, guidewires, and the like.

With continued reference to FIG. 1, the medical device 12 can be configured to be inserted into a patient's body 16, and more particularly, into the patient's heart 18. The medical device 12 may include a handle 20, a shaft 22 (e.g., elongate shaft) having a proximal end portion 24 and a distal end portion 26, and a position sensor 28 mounted in or on the shaft 22 of the medical device 12. Although one position sensor 28 is depicted in FIG. 1, embodiments of the present disclosure can include more than one position sensor 28. In an exemplary embodiment, the position sensor 28 is disposed at the distal end portion 26 of the shaft 22. The medical device 12 may further include other conventional components such as, for example and without limitation, a temperature sensor, additional sensors or electrodes, ablation elements (e.g., ablation tip electrodes for delivering RF ablative energy, high intensity focused ultrasound ablation elements, etc.), and corresponding conductors or leads.

The shaft 22 can be an elongate, tubular, flexible member configured for movement within the body 16. The shaft 22 supports, for example and without limitation, sensors and/or electrodes mounted thereon, such as, for example, the position sensor 28, associated conductors, and possibly additional electronics used for signal processing and conditioning. The shaft 22 may also permit transport, delivery, and/or removal of fluids (including irrigation fluids, cryogenic ablation fluids, and bodily fluids), medicines, and/or surgical tools or instruments. The shaft 22 may be made from conventional materials such as polyurethane, and define one or more lumens configured to house and/or transport electrical conductors, fluids, or surgical tools. The shaft 22 may be introduced into a blood vessel or other structure within the body 16 through a conventional introducer. The shaft 22 may then be steered or guided through the body 16 to a desired location, such as the heart 18, using means well known in the art.

The position sensor 28 mounted in or on the shaft 22 of the medical device 12 may be provided for a variety of diagnostic and therapeutic purposes including, for example and without limitation, electrophysiological studies, pacing, cardiac mapping, and ablation. In an exemplary embodiment, the position sensor 28 can perform a location or position sensing function. More particularly, and as will be described in greater detail below, the position sensor 28 can be configured to provide information relating to the location (e.g., position and orientation) of the medical device 12, and the distal end portion 26 of the shaft 22 thereof, in particular, at certain points in time. Accordingly, in such an embodiment, as the medical device 12 is moved along a surface of a structure of interest of the heart 18 and/or about the interior of the structure, the position sensor 28 can be used to collect location data points that correspond to the surface of, and/or other locations within, the structure of interest. These location data points can then be used for a number of purposes such as, for example and without limitation, the construction of surface models of the structure of interest. For purposes of clarity and illustration, the description below will be with respect to an embodiment with a single position sensor 28. It will be appreciated, however, that in other exemplary embodiments, which remain within the spirit and scope of the present disclosure, the medical device 12 may comprise more than one position sensor 28 as well as other sensors or electrodes configured to perform other diagnostic and/or therapeutic functions. As will be described in greater detail below, the position sensor 28 can include contact leads that are configured to electrically couple the position sensor 28 to other components of the system 10, such as, for example, the medical positioning system 14.

The medical positioning system 14 can be provided for determining a position and/or orientation of the position sensor 28 of the medical device 12, and thus, the position and/or orientation of the medical device 12. In some embodiments, and in general terms, the medical positioning system 14 comprises, at least in part, an apparatus for generating a magnetic field for tracking of an object (e.g., medical device 12). The apparatus can be configured to generate low-strength magnetic field(s) in and around the patient's chest cavity in an area of interest, which can be defined as a three-dimensional space designated as area of interest. In such an embodiment, and as briefly described above, the medical device 12 includes a position sensor 28, which is a magnetic position sensor configured to detect one or more characteristics of the low-strength magnetic field(s) applied by the apparatus when the position sensor 28 is disposed within the area of interest. The position sensor 28, which in an exemplary embodiment comprises an active magnetic sensor, can be configured to generate a signal corresponding to the sensed characteristics of the magnetic field(s) to which the active magnetic sensor is exposed. The processing core can be responsive to the detected signal and can be configured to calculate a three-dimensional position and/or orientation reading for the position sensor 28. Thus, the medical positioning system 14 enables real-time tracking of each position sensor 28 of the medical device 12 in three-dimensional space, and therefore, real-time tracking of the medical device 12. In some embodiments, the medical positioning system 14 may comprise a magnetic field-based system such as, for example, the MediGuide™ system from MediGuide Ltd. (now owned by St. Jude Medical, Inc.), and as generally shown with reference to one or more of U.S. Pat. Nos. 6,233,476; 7,197,354; and 7,386,339, the entire disclosures of which are incorporated herein by reference.

Medical positioning system 14 is configured to serve as the localization system and therefore to determine position (localization) data with respect to position sensor 28 and output a respective location reading. The location readings may each include at least one or both of a position and an orientation (P&O) relative to a reference coordinate system, which may be a coordinate system of medical positioning system 14. The P&O may be expressed with six degrees-of-freedom (six DOF) as a 3D position (e.g., X, Y, Z coordinates) and 3D orientation (e.g., roll, pitch, and yaw).

The medical positioning system 14 determines respective locations (e.g., P&O) in the reference coordinate system based on capturing and processing signals received from the electromagnetic position sensor 28 while the sensor is disposed in a controlled low-strength alternating current (AC) or direct current (DC) magnetic (e.g., electromagnetic) field, for example. It should be noted that although only one position sensor 28 is shown, MPS 22 may determine P&O for multiple position sensors 28. For example, the medical device 12 discussed herein can include a plurality of active magnetic position sensors, which can provide for a plurality of positional points associated with the medical device 12.

FIG. 2A depicts a cross-sectional side view of a distal portion of a catheter 12′ with an active magnetic position sensor 32, in accordance with embodiments of the present disclosure. In various embodiments, the catheter 12′ can include a flexible tip assembly 34, which can include, for example, a flexible tip electrode from a Therapy™ Cool Flex™ ablation catheter manufactured by St. Jude Medical, Inc. of St. Paul, Minn. Additional details regarding a flexible electrode tip may be found in, for example, U.S. Pat. No. 8,187,267 B2, United States patent application publication no. US 2010/0152731 A1, U.S. patent application Ser. No. 14/724,169, and U.S. patent application Ser. No. 14/213,289, each of which is hereby incorporated by reference as though fully set forth herein. However, in some embodiments, the catheter 12′ can include other types of tip assemblies. The flexible tip assembly 34 can be connected to a proximal stem 50, which is connected to an elongate catheter shaft 52. A coil 54 can be disposed in the flexible tip assembly 34. The coil 54 can bias the flexible tip assembly 34 in a longitudinal direction or in a pre-bent configuration. Additionally, a fluid lumen manifold 46 can extend through the elongate catheter shaft 52 into the flexible tip assembly 34.

In some embodiments, the active magnetic position sensor 32 can be an active device and can require power to function and generate a P&O signal. For example, the active magnetic position sensor 32 can include an integrated circuit that needs an amount of power to function. For example, the active magnetic position sensor 32 can include an application specific integrated circuit (ASIC). In contrast, a passive magnetic position sensor (e.g., an electromagnetic coil position sensor) can be placed in a magnetic field and can generate a P&O signal that is directly induced in the coil by the magnetic field, which can be received by the medical positioning system 14. In some embodiments, the active magnetic position sensor 32 can be a software defined magnetic sensor, such as a Triaxis® sensor produced by Melexis. The active magnetic position sensor 32 can operate in a magnetic field with a magnetic field strength in a range from 20 micro Tesslas (μT) to 120 μT. In some embodiments, the active magnetic position sensor 32 can operate in a magnetic field with a magnetic field strength in a range from 1μT to 70 μT. In an example, the magnetic position sensor 32 can operate in a magnetic field with a magnetic field strength in a range from 1μT to 20 μT and a frequency in a range from 3 to 15 kilohertz. However, the active magnetic position sensor 32 can operate in a magnetic field with a magnetic field strength that is greater than 120 μT or less than 1 μT, depending on the type of active magnetic position sensor 32 that is used. For example, some active magnetic position sensors 32 can operate in a magnetic field with a magnetic field strength of 1 milli Tessla (mT) or higher. The active magnetic position sensor 32 can produce a signal indicative of a P&O of the medical device 12. The signal indicative of the P&O of the medical device can be generated in response to detection of the magnetic field by the active magnetic position sensor. The active magnetic position sensor 32 can require power to produce the signal indicative of the P&O of the medical device, in contrast to a passive magnetic sensor.

In some embodiments, the active magnetic position sensor 32 can include a particular material that has particular magnetoresistive properties. Such a material can be placed in various geometries with respect to the active magnetic position sensor 32. The particular material can have differing magnetoresistive properties that react differently with magnetic fields. In some embodiments, reactions between the magnetoresistive properties and the magnetic fields can be measured directly. The measured reactions between the magnetoresistive properties and the magnetic field can provide an output that can be used to calculate a P&O of the active magnetic position sensor 32 in space, and thus a P&O of the catheter 12′ in space. As discussed, in some embodiments, the particular material can be arranged in a particular physical configuration with respect to the active magnetic position sensor 32. Accordingly, the particular material can provide an output that is unique to the particular physical configuration. This output can be used to calculate the P&O of the active magnetic position sensor 32.

In some embodiments, the particular material included in the active magnetic position sensor 32 can include, various types of Hall effect materials, anisotropic magnetoresistance (AMR) materials, tunnel magnetoresistance (TMR) materials, giant magnetoresistance (GMR) materials, colossal magnetoresistance (CMR) materials, or extraordinary magnetoresistance (EMR) materials. Magnetoresistance can be defined as a property of a material to change the value of its electrical resistance when an external magnetic field is applied to the material. A principal of operation that can be used in the determination of a P&O of Hall effect magnetoresistance materials can be an orbital effect, which is unrelated to a spin, due to a Lorentz force. Hall effect materials can be associated with an asymmetric distribution of charge density. A principal of operation that can be used in the determination of a P&O of AMR materials can be associated with a transverse AMR-planar effect spin-orbit interaction, which can have a negative magnetoresistance in ferromagnets. Alternatively, a principal of operation that can be used in the determination of a P&O of AMR materials can be a Shubnikov-de Haas effect (SdH), which can have a positive magnetoresistance in metals. A principal of operation that can be used in the determination of a P&O of TMR materials can be associated with electron tunneling between two ferromagnets between which is disposed a thin insulator. A magnetic field in which the ferromagnets are present can be turned on and off in the determination of the P&O of TMR materials. A principal of operation that can be used in the determination of a P&O of GMR material can be associated with electron scattering on spin orientation. The GMR material can include adjacent magnetized ferromagnetic layers. A principal of operation that can be used in the determination of a P&O of CMR materials can include spin orientation, where a conductivity of the CMR material changes as a magnetic field is aligned with an electron spin associated with the CMR material. A principal of operation that can be used in the determination of a P&O of EMR materials can be associated with the Hall effect.

In some embodiments, the active magnetic position sensor 32 can be used to determine a P&O of the catheter 12′. For example, the active magnetic position sensor 32 can determine the P&O of the catheter 12′ with six DOF. In some embodiments, the determination of the P&O of the catheter 12′ with six DOF can be used as an input for a force vector determination with respect to the catheter 12′. In some embodiments, the active magnetic position sensor 32 can determine the P&O of the catheter 12′ with fewer than six DOF. For example, the P&O of the catheter 12′ can be determined with five degrees of freedom.

In some embodiments, the active magnetic position sensor 32 can be disposed within the catheter 12′. In an example, the active magnetic position sensor 32 can be disposed along a longitudinal axis aa of the catheter 12′. In some embodiments, the active magnetic position sensor 32 can be coaxial with the longitudinal axis aa. In some embodiments, the active magnetic position sensor 32 can be disposed off-axis with respect to the longitudinal axis aa. For example, an elongate axis of the active magnetic position sensor 32 can be parallel with the longitudinal axis aa and/or can be divergent with the longitudinal axis aa. In some embodiments, the active magnetic position sensor 32 can be disposed in a same place where a passive magnetic position sensor (e.g., an electromagnetic coil position sensor) would be placed. For example, the active magnetic position sensor 32 can be disposed in a same place as magnetic coil assembly 38. As previously discussed, the magnetic coil assembly 38 may not be included in the catheter 12′, since a P&O of the catheter 12′ can be determined instead through the active magnetic position sensor 32.

For illustrative purposes, the catheter 12′ is shown with ring electrodes 36-1, 36-2, 36-3 and a magnetic coil assembly 38. The magnetic coil assembly 38 is depicted as connected to a printed circuit board 40 via a pair of interconnects. The printed circuit board 40 is mounted on a mounting surface 42. A twisted pair 44 can connect the magnetic coil assembly 38 to the medical positioning system 14. In some embodiments of the present disclosure, the ring electrodes 36-1, 36-2, 36-3 and the magnetic coil assembly 38 are not needed, as the P&O of the catheter 12′ can be detected via the active magnetic position sensor 32. For example, the active magnetic position senor can be the only position sensor included in the catheter 12′.

As depicted in FIG. 2B, the active magnetic position sensor 32 can be disposed next to the irrigation tube 46 and proximally with respect to the stop tube 48. In some embodiments, the active magnetic position sensor 32 can be disposed within the stop tube 48 or within the proximal stem 50 that is connected to the flexible tip assembly 34. In an example, a mounting feature such as a groove or hole can be included in the stop tube 48 or the proximal stem 50 and the active magnetic position sensor 32 can be inserted into the hole. However, in some embodiments, the active magnetic position sensor 32 can be disposed within the catheter 12′ at other locations.

Embodiments of the present disclosure can provide an active magnetic position sensor 32 that provides the P&O of the catheter 12′ with six DOF using a single sensor. In contrast, many single coil sensors used in prior approaches can be limited to five DOF. In addition, the active magnetic position sensor 32 can have a form factor that can allow the active magnetic position sensor 32 to be placed in a wide variety of devices, due to its small size. Further, the active magnetic position sensor 32 can provide for savings related to a cost of goods associated with use of the active magnetic position sensor 32 and a cost of labor associated with constructing and installing the active magnetic position sensor 32.

FIG. 2B depicts a side view of an active magnetic position sensor 32, in accordance with embodiments of the present disclosure. In some embodiments, the active magnetic position sensor 32 can be elongated and sized to fit within a catheter. In contrast to present active magnetic position sensors, the active magnetic position sensor 32 can be smaller to enable it to fit within a catheter. In some embodiments, the active position sensor 32 can have an outside diameter defined by line bb, in a range from 0.001 inches to 0.015 inches. In some embodiments, the outside diameter of the active magnetic position sensor 32 can be in a range from 0.003 inches to 0.01 inches. However, in some embodiments, the outside diameter of the active magnetic position sensor 32 can be less than 0.001 inches or greater than 0.015 inches. In some embodiments, a length of the active magnetic position sensor 32 defined by line cc can be in a range from 0.03 inches to 0.2 inches. In some embodiments, the length of the active magnetic position sensor 32 can be in a range from 0.05 inches to 0.1 inches. However, in some embodiments, the length of the active magnetic position senor 32 can be less than 0.03 inches or greater than 0.2 inches. In some embodiments, the active magnetic position sensor 32 can be in the shape of a rectangular block or a cylinder, among other shapes.

The active magnetic position sensor 32 can include contact pads 56-1, 56-2, 56-3, 56-4. Hereinafter, the contact pads 56-1, 56-2, 56-3, 56-4 are collectively referred to as contact pads 56. The contact pads 56 can provide connection points (e.g., inputs and outputs) for power and/or communication with the active magnetic position sensor 32 (e.g., with the medical positioning system 14). Although four contact pads 56 are depicted, the active magnetic position sensor can include fewer than four contact pads or greater than four contacts pads. In some embodiments, the active magnetic position sensor 32 can be a quad flat no-lead sensor and can be connected to a printed circuit board via the contact pads 56. For example, the active magnetic position sensor 32 can be connected via a pair of interconnects to a printed circuit board, such as printed circuit board 40 depicted in FIG. 2A, and/or the medical positioning system 14.

In some embodiments, the contact pads 56 can provide for an input and output from the active magnetic position sensor 32. For example, an input power can be provided to and/or communication can be established with the active magnetic position sensor 32 via the contact pads 56, enabling receipt of a signal produced by the active magnetic position sensor 32. Power can be provided to the active magnetic position sensor 32 via a power source that is electrically coupled to one or more of the contact pads 56. In an example, one or more electrical leads can extend through the elongate catheter shaft 52 to the active magnetic position sensor 32. In some embodiments, a power generating integrated circuit (e.g., power source) can be disposed in the catheter 12′ and/or within a magnetic field generated by the medical positioning system 14. The power generating integrated circuit can pick up the magnetic field and generate a voltage/current, which can be provided to the magnetic position sensor 32. In some embodiments, the power generating integrated circuit can be included in the active magnetic position sensor, disposed in close proximity to the active magnetic position sensor 32 (e.g., in a shaft distal portion) or in another portion of the elongate catheter shaft 52 (e.g., shaft proximal portion) that is positioned within the magnetic field produced by the medical positioning system. In some embodiments, the power generating integrated circuit can be positioned within the magnetic field produced by the medical positioning system, but outside of the elongate catheter shaft 52. Power can be provided to the active magnetic position sensor 32 via contact pads 56, in some embodiments. In some embodiments, a first contact pad 56-1 can serve as an electrical ground and a second contact pad 56-2 can be a power connect.

In some embodiments, the contact pads 56 can provide for an output from the active magnetic position sensor 32. In some embodiments, signal processing can be performed on the output from the active magnetic position sensor 32 by a signal processor. The signal processor can perform filtering and/or amplification of the signal produced by the active magnetic position sensor and can be electrically coupled to one or more of the contact pads (e.g., third contact pad 56-3, fourth contact pad 56-4). In some embodiments, the signal processor can be disposed in the catheter 12′. In some embodiments, the signal processor can be included in the active magnetic position sensor, disposed in close proximity to the active magnetic position sensor 32 (e.g., in a shaft distal portion) or in another portion of the elongate catheter shaft 52 (e.g., shaft proximal portion). In some embodiments, the signal processor can be disposed outside of the elongate catheter shaft 52 (e.g., in the magnetic positioning system 14 or elsewhere). Positioning the signal processor in close proximity to the active magnetic position sensor 32 can reduce signal noise that can develop in electrical leads that connect the active magnetic position sensor 32 and the signal processor. As a length of the electrical leads that connect the active magnetic position sensor 32 and the signal processor increase the signal passing through the leads can pick up signal noise. Accordingly, by positioning the signal processor in close proximity to the active magnetic position sensor 32, the signal can be less affected by signal noise.

As depicted in FIG. 2B, a first set of contact pads, including a first contact pad 56-1 and second contact pad 56-2 are longitudinally aligned and disposed on a first side of the active magnetic position sensor 32. A second set of contact pads, including a third contact pad 56-3 and a fourth contact pad 56-4 can be longitudinally aligned and disposed on a second side of the active magnetic position sensor 32. In some embodiments, the first set of contact pads 56-1, 56-2 can be longitudinally staggered and diametrically opposed to the second set of contact pads 56-3, 56-4. The first set of contact pads 56-1, 56-2 and the second set of contact pads 56-3, 56-4 can be disposed on a proximal half of the active magnetic position sensor 32. By doing so, less wiring can be used to electrically couple the contact pads 56 of the active magnetic position sensor 32 to the magnetic positioning system 14, which can reduce a bulk associated with internal components of the catheter 12′.

FIG. 3A depicts a cross-sectional side view of a distal portion of a guidewire 12″ with an active magnetic position sensor 72, in accordance with embodiments of the present disclosure. The guidewire 12″ can be a deflectable guidewire, in some embodiments, as depicted in FIG. 3B. As such, the guidewire 12″ can include a core wire 74, in some embodiments. The guidewire 12″ can have an outer coating 76 that surrounds the contents of the guidewire 12″. In an example, the core wire 74 can extend through a center of the guidewire 12″ from a proximal end to a distal end of the guidewire 12″. In some prior approaches, an magnetic coil 78 can be disposed within a distal end of the guidewire 12″. For example, the core wire 74 can extend through a center of the magnetic coil 78, in some embodiments. For illustrative purposes, the magnetic coil 78 is shown disposed in the distal end of the guidewire 12″. In some embodiments of the present disclosure, the magnetic coil 78 is not needed, as the active magnetic position sensor 72 can be used to detect the P&O of the catheter 12′.

In some embodiments, as discussed herein, the active magnetic position sensor 72 can be smaller than a traditional magnetic coil (e.g., passive magnetic position sensor). For example, the active magnetic position sensor 72 can have a length that is approximately half that of a traditional coil, as depicted in FIG. 3B. For example, a traditional magnetic coil can have a length defined by the line DD, which can be in a range from 0.2 to 0.28 inches. A length of a traditional magnetic coil, including interconnects for connecting the coil, can be longer than desired. A longer than desired length of the magnetic coil can affect a flexibility and/or deflection of a catheter shaft in which the coil is included. In addition, the longer than desired length of the magnetic coil can occupy real estate in the distal end of the guidewire, which could be used for other components. Further, the active magnetic position sensor 72 can be cheaper to produce and install than a traditional magnetic coil.

As depicted in FIG. 3A, the active magnetic position sensor 72 can be disposed in a distal end of the guidewire 12″ and proximally with respect to a distal tip 80 of the guidewire. The active magnetic position sensor 72 can be the same as and can include the same features as the active magnetic position sensor 32, as discussed in relation to FIGS. 2A and 2B. In some embodiments, the active magnetic position sensor 72 can be disposed within the guidewire 12″, which has a smaller outer diameter than the catheter 12′. Thus, in some embodiments, the active magnetic position sensor 72 can have a diameter that is smaller than the active magnetic position sensor 32 placed in the catheter 12′. For example, space in the catheter 12′ can limit an outer diameter of the active magnetic position sensor 32 to 0.015 inches, in some embodiments. However, space within the guidewire 12″ can limit an outer diameter of the active magnetic position sensor 72 to 0.0038 inches. As such, the active magnetic position sensor 72 can have an outer diameter that is less than 0.0038 inches, in some embodiments. For example, the magnetic position sensor 72 can have an outer diameter in a range from 0.001 to 0.0038, in some embodiments.

In some embodiments, the active magnetic position sensor 72 can be positioned between the core wire 74 and the outer coating 76. An elongate axis of the active magnetic position sensor 72 can be parallel with a longitudinal axis of the guidewire 12″, in some embodiments. Alternatively, the elongate axis of the active magnetic position sensor 72 can be divergent with the longitudinal axis of the guidewire 12″, in some embodiments.

FIG. 3B depicts a diagrammatic side view of an active magnetic position sensor 72 for use with a guidewire 12″, in accordance with embodiments of the present disclosure. As depicted in FIG. 3B, the active magnetic position sensor 72 can be disposed in a distal portion of the guidewire 12″. As depicted in FIG. 3B, the active magnetic position sensor 72 can be less than one-half of a length of a traditional magnetic coil. This can allow for space savings in the guidewire and less interference with a deflectable portion of the guidewire 12″, for example.

In some embodiments, the active magnetic position sensor 72 can operate based on Hall Effect physics for detection of the magnetic field. However, the active magnetic position sensor 72 can operate off of other principles for the detection of the magnetic field, as discussed herein. In some embodiments, the active magnetic position sensor 72 can be a microelectricalmechanical (MEM) sensor.

When traditional magnetic coils are used as magnetic position sensors, the coil can be connected to interconnects (e.g., wire leads) via soldering. This process can be time and cost intensive and may require a person to manually solder the coil and the interconnects together. Embodiments of the present disclosure can provide an active magnetic position sensor 72 that can be mounted to a printed circuit board via surface mount technology, which can be automated. Thus, a cost of the active magnetic position sensor 72 and installation of the active magnetic position sensor 72 can be reduced.

FIG. 3B depicts the distal tip of the guidewire 12″ as being deflected by a particular angle θ, which is depicted as 35 to 45 degrees. In prior approaches that use a traditional magnetic coil, deflection of the distal portion of the guidewire 12″ may be limited to a deflection in a range from 35 to 45 degrees, as a result of the magnetic coil being positioned in the distal portion. However, use of the active magnetic position sensor 72 may enable a more distal portion of the guidewire 12″ to be deflected because of a shorter length that can be associated with the active magnetic position sensor 72 and/or enable the guidewire 12″ to deflect by a greater angle θ. For example, the guidewire 12″ can be deflected by 75 degrees when the active magnetic position sensor 72 is used instead of a traditional magnetic coil. This can improve a performance of the guidewire 12″, by allowing for an increased length of the guidewire 12″ to be deflected over that associated with a guidewire that utilizes a traditional magnetic coil.

FIG. 3C depicts a proximal end 90 view of a sensor mounting plug 92, in accordance with embodiments of the present disclosure. FIG. 3D depicts an isometric side and proximal end 90 view of the sensor mounting plug 92, in accordance with embodiments of the present disclosure. As depicted, the sensor mounting plug 92 can include a proximal end 90 and a distal end 94 and can extend along a longitudinal axis. In some embodiments, the sensor mounting plug 92 can define a central lumen 96 through which various components can pass. The central lumen 96 can extend through a center of the sensor mounting plug 92 along a longitudinal axis defined by the sensor mounting plug 92. Although the central lumen 96 is depicted as extending through the center of the sensor mounting plug 92, the central lumen 96 can be offset from the center of the sensor mounting plug 92, in some embodiments, to house a pull wire. In some embodiments, the sensor mounting plug 92 can define a sensor mounting lumen 98, in which an active magnetic position sensor 72 can be inserted. The sensor mounting lumen 98 can extend through the sensor mounting plug 92 and can be offset from the center of the sensor mounting plug 92 (e.g., located to the side of the central lumen 96). In some embodiments, the sensor mounting lumen 98 can extend through the entire longitudinal length of the sensor mounting plug 92 (e.g., a thru hole) or can extend through a portion of the longitudinal length of the sensor mounting plug 92 (e.g., a blind hole).

In some embodiments, the outer coating 76 can be in contact and connected with the outer circumferential surface of the sensor mounting plug 92, which can help to fix the sensor mounting plug 92 in relation to the guidewire 12″. In some embodiments, the longitudinal axis of the sensor mounting plug 92 can be aligned with the longitudinal axis of the guidewire 12″. In some embodiments, the sensor mounting plug 92 can be connected with the distal tip 80 and/or the sensor mounting plug 92 and the distal tip 80 can be formed as a unitary piece with a sensor mounting hole extending distally through a portion of the sensor mounting plug 92 from a proximal end of the sensor mounting plug 92. The sensor mounting plug 92 can be disposed proximally with respect to the distal tip 80. In some embodiments, the sensor mounting plug 92 can be disposed adjacent and proximally with respect to the distal tip 80.

In some embodiments, the sensor mounting plug 92 can be disposed in a catheter shaft, such as a catheter shaft depicted in FIGS. 2A and 2B. The sensor mounting plug 92 can include more than two lumens. For example, the sensor mounting plug 92 can include a plurality of lumens passing therethrough, in which wires or other components (e.g., an irrigation tube, core wire, pull wire, etc.) can be housed. For example, components associated with the flexible tip assembly 34 can pass through lumens included in the sensor mounting plug 92.

FIG. 3E depicts a cross-sectional side view of a guidewire 12′″ with an active magnetic position sensor 72′ and a sensor mounting plug 92′, in accordance with embodiments of the present disclosure. FIG. 3E depicts a guidewire 12′ with features similar to those discussed in relation to FIG. 3A, with the addition of the sensor mounting plug 92, but with no magnetic coil depicted. The guidewire 12′ can include a core wire 74′, in some embodiments. The guidewire 12′″ can have an outer coating 76′ that surrounds the contents of the guidewire 12′″. In an example, the core wire 74′ can extend through a center of the guidewire 12′ from a proximal end to a distal end of the guidewire 12′.

As depicted in FIG. 3E, the active magnetic position sensor 72′ can be disposed in a distal end of the guidewire 12′″ and proximally with respect to a distal tip 80′ of the guidewire guidewire 12′″. The active magnetic position sensor 72′ can be the same as and can include the same features as the active magnetic position sensor 32, as discussed in relation to FIGS. 2A and 2B. In some embodiments, the active magnetic position sensor 72′ can be disposed within the guidewire 12′, which has a smaller outer diameter than the catheter 12′. Thus, in some embodiments, the active magnetic position sensor 72′ can have a diameter that is smaller than the active magnetic position sensor 32 placed in the catheter 12′. For example, space in the catheter 12′ can limit an outer diameter of the active magnetic position sensor 32 to 0.015 inches, in some embodiments. However, space within the guidewire 12″ can limit an outer diameter of the active magnetic position sensor 72′ to 0.0038 inches. As such, the active magnetic position sensor 72′ can have an outer diameter that is less than 0.0038 inches, in some embodiments. For example, the magnetic position sensor 72′ can have an outer diameter in a range from 0.001 to 0.0038, in some embodiments.

In some embodiments, the active magnetic position sensor 72′ can be positioned between the core wire 74′ and the outer coating 76′. An elongate axis of the active magnetic position sensor 72′ can be parallel with a longitudinal axis of the guidewire 12′, in some embodiments. Alternatively, the elongate axis of the active magnetic position sensor 72′ can be divergent with the longitudinal axis of the guidewire 12′, in some embodiments.

The active magnetic position sensor 72′ can be housed in a sensor mounting lumen 98′ defined by the sensor mounting plug 92′. As depicted, the sensor mounting plug 92′ can extend along a longitudinal axis. In some embodiments, the sensor mounting plug 92′ can define a central lumen through which various components can pass (e.g., central lumen 96), which in some embodiments can extend along a longitudinal axis defined by the sensor mounting plug 92′ and through the center of the sensor mounting plug 92 and/or can be offset from the center of the sensor mounting plug 92′. In some embodiments, the sensor mounting plug 92′ can define a sensor mounting lumen 98′, in which the active magnetic position sensor 72′ can be inserted. The sensor mounting lumen 98′ can extend through the sensor mounting plug 92′ and can be offset from a central longitudinal axis of the sensor mounting plug 92′. Due to a limited space which can be present in catheters and/or guidewires, the lumens defined by the sensor mounting plug 92′ can be connected (e.g., form a slot). For example, with reference to FIGS. 3C and 3D, an inner wall is depicted between the central lumen 96 and the sensor mounting lumen 98 and an outer wall is depicted between the sensor mounting lumen 98 and an outer surface of the sensor mounting plug 92. In contrast, FIG. 3E depicts no wall between the central lumen and the sensor mounting lumen 98′ and no wall between the sensor mounting lumen 98′ and an outer surface of the sensor mounting plug 92′, effectively forming a slot in which the active position sensor 72′ is disposed. In some embodiments, more space can be available in a catheter than a guidewire and thus the sensor mounting lumen 98′ and various other lumens defined by the sensor mounting plug 92′ can remain as separate lumens with walls disposed between them. In some embodiments, the sensor mounting lumen 98′ can extend through the entire longitudinal length of the sensor mounting plug 92′ (e.g., a thru hole) or can extend through a portion of the longitudinal length of the sensor mounting plug 92′ (e.g., a blind hole).

In some embodiments, the outer coating 76′ can be in contact and connected with the outer circumferential surface of the sensor mounting plug 92′, which can help to fix the sensor mounting plug 92′ in relation to the guidewire 12′. In some embodiments, the longitudinal axis of the sensor mounting plug 92′ can be aligned with the longitudinal axis of the guidewire 12′. In some embodiments, the sensor mounting plug 92′ can be connected with the distal tip 80′ and/or the sensor mounting plug 92′ and the distal tip 80′ can be formed as a unitary piece with a sensor mounting hole extending distally through a portion of the sensor mounting plug 92′ from a proximal end of the sensor mounting plug 92′. The sensor mounting plug 92′ can be disposed proximally with respect to the distal tip 80′. In some embodiments, the sensor mounting plug 92′ can be disposed adjacent and proximally with respect to the distal tip 80′.

In some embodiments, the sensor mounting plug 92′ can be disposed in a catheter shaft, such as a catheter shaft depicted in FIGS. 2A and 2B. The sensor mounting plug 92′ can include more than two lumens. For example, the sensor mounting plug 92′ can include a plurality of lumens passing therethrough, in which wires or other components (e.g., an irrigation tube, core wire, pull wire, etc.) can be housed. For example, components associated with the flexible tip assembly 34 can pass through lumens included in the sensor mounting plug 92′.

FIG. 4 depicts a method flow diagram for determining a P&O of a medical device, in accordance with embodiments of the present disclosure. In some embodiments, the method can include generating a signal with an active magnetic position sensor disposed within an elongate shaft of the medical device, at method flow box 110. The active magnetic position sensor can generate the signal in response to being disposed in a magnetic field, which can be generated by a magnetic field generator. In some embodiments, the magnetic field generator can be in communication with the magnetic positioning system.

The method can include, at method flow box 112, receiving, with a computer, the generated signal from the active magnetic position sensor, wherein the received signal includes information indicative of a P&O of the active magnetic position sensor. In some embodiments, the computer can be in communication with or part of the magnetic positioning system. The signal can be received with a magnetic positioning system, as previously discussed herein. The active magnetic position sensor can be provided power, in contrast to a traditional magnetic coil sensor, which is a passive type of sensor, requiring no power. Power can be supplied to the active magnetic position sensor via a power generating integrated circuit, which is electrically coupled to the active magnetic position sensor. In some embodiments, power can be supplied to the active magnetic position sensor via the magnetic positioning system, which is electrically coupled to the active magnetic position sensor. Providing power to the active magnetic position sensor enables the active magnetic position sensor to produce a signal that is indicative of a particular P&O in the magnetic field.

In some embodiments, the method can include determining, with the computer, the P&O of the medical device based on the generated signal, at method flow box 114. In an example, the computer can be associated with or in communication with the magnetic positioning system and can determine the P&O of the medical device with six degrees of freedom. Although the P&O of the medical device is determined with six degrees of freedom, the P&O can be determined with fewer than six degrees of freedom (e.g., three degrees of freedom, five degrees of freedom).

FIG. 5 illustrates a block diagram of an example of a computer-readable medium in communication with processing resources of a computing device, in accordance with embodiments of the present disclosure. The computer system 120, as discussed in relation to FIG. 1, can utilize software, hardware, firmware, and/or logic to perform a number of functions. The computer system 120 can include a number of remote computing devices.

The computer system 120 can be a combination of hardware and program instructions configured to perform a number of functions, and in some embodiments can be representative of the magnetic positioning system 14. The hardware, for example, can include one or more processing resources 122, computer readable medium (CRM) 124, etc. The program instructions (e.g., computer-readable instructions (CRI) 126) can include instructions stored on CRM 124 and executable by the processing resource 122 to implement a desired function (e.g., determine the P&O of the medical device based on the signal, etc.). The CRI 126 can also be stored in remote memory managed by a server and represent an installation package that can be downloaded, installed, and executed. The computer system 120 can include memory resources 128, and the processing resources 122 can be coupled to the memory resources 128.

Processing resources 122 can execute CRI 126 that can be stored on an internal or external non-transitory CRM 124. The processing resources 122 can execute CRI 126 to perform various functions, including the functions described with respect to FIG. 1 to FIG. 4.

A number of modules 130, 132, 134 can be sub-modules or other modules. For example, the generating module 130 and the receiving module 132 can be sub-modules and/or contained within a single module. Furthermore, the number of modules 103, 132, 134 can comprise individual modules separate and distinct from one another.

A receiving surface model module 67 can comprise CRI 66 and can be executed by the processing resource 32 to receive a surface model of the heart 10 corresponding to an end diastole phase of a cardiac cycle. The surface model of the heart 10 can be formed from location data received from the electrode 17 and can correspond to a reference cardiac phase (e.g., end diastole phase). Alternatively, the surface model of the heart 10 can be generated at a previous time and received via the computer system 20.

A generating module 130 can comprise CRI 126 and can be executed by the processing resource 122 to generate a signal with an active magnetic position sensor disposed within an elongate shaft of the medical device. As discussed herein, the active magnetic position sensor can generate the signal, which is indicative of a P&O of the active magnetic position sensor and thus the medical device. In some embodiments, the active magnetic position sensor can generate the signal in response to being placed in a magnetic field.

A receiving module 132 can comprise CRI 126 and can be executed by the processing resource 122 to receive, with a computer, the generated signal from the active magnetic position sensor, wherein the received signal includes information indicative of a P&O of the active magnetic position sensor. In some embodiments, the active magnetic position sensor can be in communication (e.g., wired or wireless) with a magnetic positioning system. The magnetic positioning system can receive the generated signal in some embodiments.

A determining module 134 can comprise CRI 126 and can be executed by the processing resource 122 to determine, with the computer, the P&O of the medical device based on the generated signal. As discussed herein, the P&O of the medical device can be determined with six degrees of freedom.

Embodiments are described herein of various apparatuses, systems, and/or methods. Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and depicted in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments, the scope of which is defined solely by the appended claims.

Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment”, or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment(s) is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment,” or the like, in places throughout the specification, are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features, structures, or characteristics of one or more other embodiments without limitation given that such combination is not illogical or non-functional.

It will be appreciated that the terms “proximal” and “distal” may be used throughout the specification with reference to a clinician manipulating one end of an instrument used to treat a patient. The term “proximal” refers to the portion of the instrument closest to the clinician and the term “distal” refers to the portion located furthest from the clinician. It will be further appreciated that for conciseness and clarity, spatial terms such as “vertical,” “horizontal,” “up,” and “down” may be used herein with respect to the illustrated embodiments. However, surgical instruments may be used in many orientations and positions, and these terms are not intended to be limiting and absolute.

Although at least one embodiment of an active magnetic position sensor has been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this disclosure. All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of the devices. Joinder references (e.g., affixed, attached, coupled, connected, and the like) are to be construed broadly and can include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relationship to each other. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure can be made without departing from the spirit of the disclosure as defined in the appended claims.

Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated materials does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material. 

What is claimed is:
 1. A medical device, comprising: an elongate shaft extending along a shaft longitudinal axis and comprising a shaft proximal portion and a shaft distal portion that is sized and configured for insertion into a body; and an active magnetic position sensor disposed within the shaft distal portion.
 2. The medical device of claim 1, wherein: the elongate shaft is a catheter shaft that includes a flexible tip assembly connected to a distal end of the elongate shaft; and the active magnetic position sensor is disposed proximally with respect to the flexible tip assembly.
 3. The medical device of claim 1, wherein the active magnetic position sensor produces a signal indicative of a position and orientation of the medical device, wherein the signal indicative of the position and orientation of the medical device is generated in response to detection of a magnetic field by the active magnetic position sensor.
 4. The medical device of claim 3, wherein the active magnetic position sensor requires power to produce the signal indicative of the position and orientation of the medical device.
 5. The medical device of claim 3, wherein the signal produced by the active magnetic position sensor is indicative of the position and orientation of the medical device with six degrees of freedom.
 6. The medical device of claim 5, further comprising: a power source electrically coupled with the active magnetic position sensor; and a signal processor electrically coupled with the active magnetic position sensor.
 7. The medical device of claim 6, wherein the power source is a power generating integrated circuit, which produces power in response to being positioned in the magnetic field.
 8. The medical device of claim 7, wherein the power generating integrated circuit is disposed in the elongate shaft of the medical device.
 9. The medical device of claim 7, wherein the power generating integrated circuit is disposed outside of the elongate shaft of the medical device.
 10. The medical device of claim 3, wherein the magnetic field is generated by a magnetic field generator, and wherein the magnetic field generator and the active magnetic position sensor are in communication with a medical positioning system.
 11. The medical device of claim 1, wherein: the medical device is a guidewire that includes a core wire that extends through a center of the guidewire from a proximal end of the guidewire to a distal end of the guidewire; and the active magnetic position sensor is disposed between the core wire and an outer surface of the guidewire.
 12. A medical device, comprising: an elongate shaft extending along a shaft longitudinal axis and comprising a shaft proximal portion and a shaft distal portion that is sized and configured for insertion into a body; an active magnetic position sensor disposed within the distal portion of the elongate shaft; and a power source electrically coupled with the active magnetic position sensor.
 13. The medical device of claim 12, wherein a sensor mounting plug is included in the shaft distal portion.
 14. The medical device of claim 13, wherein the active position sensor is disposed within a lumen formed in the sensor mounting plug.
 15. The medical device of claim 12, wherein the sensor mounting plug is connected with a distal tip of the elongate shaft.
 16. A method for determining a position and orientation of a medical device, comprising: generating a signal with an active magnetic position sensor disposed within an elongate shaft of the medical device; receiving, with a computer, the generated signal from the active magnetic position sensor, wherein the received signal includes information indicative of a position and orientation of the active magnetic position sensor; and determining, with the computer, the position and orientation of the medical device based on the generated signal.
 17. The method of claim 16, further comprising providing power to the active magnetic position sensor.
 18. The method of claim 17, wherein the power is provided to the active magnetic position sensor via a power generating integrated circuit.
 19. The method of claim 17, wherein the power is provided to the active magnetic position sensor via a magnetic field generated by a magnetic positioning system.
 20. The method of claim 16, wherein determining the position and orientation includes determining the position and orientation of the medical device with six degrees of freedom. 